Adding Shift Hotkeys To Virtual Instruments To Extend Note Range Of Keyboard

Each virtual instrument provides a virtual keyboard at the bottom of its window.
(If no conflicts) may be a nice idea to add hotkeys where if you hold down the LEFT shift button and play notes (on your computer keyboard) you are playing in octaves BELOW current position, and if you do the same with the RIGHT shift you can play in octaves ABOVE.
(I did not make this up, got the idea from another program, and it may be useful in LMMS)
Just gives you more range on a computer keyboard without having to move the green square.

On a side note:
Might be confusing to implement, but at times it may be nice for some way of viewing a FULL vertical virtual keyboard graphic on your screen to show you where you are playing.

Thank You

No files, tests, or entry points are named. Begin by locating the virtual instrument keyboard input handling and determine how left and right Shift interact with existing shortcuts; done should mean the computer keyboard can reach lower and higher octaves without moving the current position, with any full-keyboard view treated as a separate scope decision.

Written by the indexing model from the issue text.